Power groover



United States Patent POWER GROOVER James A. Myklebust and Harry A. Hanly, Longview, Wash.

Application April 15, 1953, Serial No. 348,933

2 Claims. (Cl. 164-10.2)

This invention relates to power groovers. In particular, the invention i directed to groovers for cutting rib treads in tires prior to vapor cure recapping.

The objects of the invention are to produce an attachment for a power groover by means of which tie bars are automatically produced when cutting grooves in tires prior to recapping, and thereby prevent channel cracking. In general these objects are accomplished by attaching a wheel turned cam to a power groover, said cam lifting and lowering a lever which in turn lifts and lowers the grooving knife and thereby leaving a tie bar across the groove being out every time the knife is lifted.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying drawings, in which:

Figure 1 is a plan view of the power groover;

Figure 2 is a front elevational view of Figure 1;

Figure 3 is a cross-sectional view on the line 33, Figure 1;

Figure 4 is a cross-sectional view on the line 44, Figure 1; and

Figure 5 is a cross-sectional view on the line 55, Figure 3.

A power groover is composed of a handle 2 having a bifurcated end 4 pivotally connected to a support 6. An electrically heated knife 8 is carried by handle 2. A tire T, note Figure 3 is power rotated and the knife 8 manually brought in cutting engagement with the tire by lowering handle 2.

To the above knife and handle, the present invention adds means for automatically raising and lowering the knife so that tie bars will be left in the groove being cut. Below the bight of bifurcated handle end 4, a block 10 is mounted by means of threaded stud 12 and nut 14. Block 10 has a slot 16 for receiving one end of a lever 18. A pair of arms 20 are pivotally connected to block 10, on opposite sides thereof, by a bolt 22, said bolt also pivotally ecuring an end of lever 18. Spring 21 extending between handle 2 and arms 20 elastically hold the arms in position.

A shaft 24 is journaled in the free ends of arms 20, and a pair of wheels 26 are secured to the ends of the shaft outwardly of the arms. The wheels have knurled treads so that they can be frictionally turned by a rotating tire. Collars 28 integral with wheels 26 serve to space the wheels slightly outwardly of arms 20. Pins (not shown) may be inserted through collars 28 into shaft 24 to fasten the wheels to the shaft. A cam 30 is fixed to the center portion of shaft 24 between arms 20.

Lever 18 has a bifurcated free end into which is 2,748,859 Patented June 5, 1956 mounted a roller 32 which serves as a cam follower riding upon cam 30. The bottom edge of the lever is relieved at 31 in order to allow for the passage of the cam 30. An adjusting screw 34 threaded in handle 2 bears against lever 18 so that movement of the lever is transmitted to the handle.

In operation the tire T is rotated on a stand by a motor or other means. To cut a groove, the handle 2 is lowered so that the wheels 26 rest on the circumferential surface of the tire. The depth of the cut to be made is fixed by adjusting screw 34, and knife 8 cuts a groove in the tire. As the tire revolves it turns Wheels 26, which rotates shaft 24 and cam 30. Roller 32 is raised and lowered by cam 30 so that arm 18 by reason of screw 34 raises and lowers handle 2, thus lifting and lowering knife 8 so that tie bars are left in the groove when the knife is lifted. Springs 21 permit the wheels 26 to rest on tires of various diameters while keeping the arms 20 from falling to a vertical position when the tire is shifted or changed.

The invention is adapted for use with any type of power groover or stitcher, and is particularly adapted for grooving tires which are to be recapped by the vapor cure method. In addition to the setting of the depth of cut by means of screw 34, the depth of cut or the frequency of lifting the handle to form tie bars can be made different by changing the cam 30. By substituting wheels of different diameter for wheels 26, the distance between tie bars may be varied.

Having now described the means by which the objects of the invention are obtained, we claim:

1. A tire tie bar maker comprising a handle, means for pivotally securing one end of said handle to a fixed support whereby said handle is manually movable toward and from the circumference of a tire, a knife mounted on said handle, a lever pivotally secured to said handle between said knife and the pivotally secured end of said handle, an axle journaled in the free end of said lever and having a wheel mounted thereon and adapted to ride on the circumference of a tire, a cam on said axle and turnable thereby, a cam follower for said cam, a second lever carrying said cam follower, and means carried by said handle for adjusting said second lever in relation to said handle whereby the rotation of the cam raises and lowers the handle and knife in relation to said tire.

2. A tie bar maker as in claim 1, further comprising spring means between said handle and lever for holding said cam into contact with said cam follower.

References Cited in the file of this patent UNITED STATES PATENTS 64,420 Holroyd May 7, 1867 649,905 Brophy May 22, 1900 1,605,924 Dodd Nov. 9, 1926 1,864,903 Gora June 28, 1932 1,894,347 Dacon et a1. Jan. 17, 1933 1,925,498 Plante Sept. 5, 1933 1,971,582 Scruby Aug. 28, 1934 1,986,587 Ludington Jan, 1, 1935 1,996,176 Smith Apr. 2, 1935 2,362,967 Bivans Nov. 21, 1944 FOREIGN PATENTS 128,948 Australia Aug. 30, 1948 

